[colug-432] RPi peripheral power consumption

jep200404 at columbus.rr.com jep200404 at columbus.rr.com
Sat May 18 11:39:27 EDT 2013

On Sat, 18 May 2013 09:59:46 -0400, Scott Merrill <skippy at skippy.net> wrote:

> Can someone tell me - in general - which would draw more power on a
> Raspberry Pi: a USB WiFi adapter or the onboard Ethernet port?

That depends on the USB Wifi adapter. I have an old one that I 
think pulls around 450 mA. That's much for any USB thing, 
and much more than the ethernet port uses. 
However, for newer Wifi adapters, althought I just don't _know_ 
how much power they use, it's likely to be much less than my 
old Wifi adapter. 

Look at the output of lsusb to see the claimed max power for 
each USB thing you try. IIRC, the Pi's ethernet port is a USB 

I guess in your case the power supply comparison would be 
USB Wifi versus _incremental_ power used by ethernet port 
when something is plugged into it and schlepping bits back 
and forth. 

> Or is the power draw differential so inconsequential as to not be worth
> worrying about?

That depends on what your power concerns are. If you are running 
on batteries, it can be a big big concern. My Pi was flaky because 
the wall wart I was using just was not powerful enough. After I 
started using a more powerful wall wart, it became reliable. 
In some other applications, heat can be a concern. 

Besides curiosity, what power concerns do you have? 

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